Testosterone Decanoate API is a synthetic ester of testosterone belonging to the androgen class. It is chemically the 17β-decanoate ester of testosterone, formed by esterification of the 17β-hydroxyl group of testosterone with decanoic acid. PubChem identifies Testosterone Decanoate as a steroid ester with the molecular formula C₂₉H₄₆O₃ and molecular weight 442.7 g/mol.
Testosterone decanoate is also known as testosterone caprate and testosterone 17β-decanoate. Its CAS number is 5721-91-5, and FDA GSRS assigns the substance UNII IJW60LAO6S.
The substance has a European Pharmacopoeia monograph, Testosterone Decanoate, Ph. Eur. monograph 1736, making pharmacopoeial specifications available for important quality attributes including assay, related substances, specific optical rotation and loss on drying.
Testosterone decanoate is a long-chain fatty-acid ester of testosterone. Esterification changes the physicochemical and pharmacokinetic characteristics of testosterone compared with the parent hormone. It is a lipophilic steroid ester and is practically insoluble in water. The BP 2025/Ph. Eur. 11.6 monograph describes it as a white or almost white powder and reports that it is very soluble in acetone, methylene chloride and anhydrous ethanol and freely soluble in fatty oils.
| Property | Value |
|---|---|
| Product Name | Testosterone Decanoate |
| CAS Number | 5721-91-5 |
| UNII | IJW60LAO6S |
| Molecular Formula | C₂₉H₄₆O₃ |
| Molecular Weight | 442.7 g/mol |
| Chemical Class | Testosterone Ester |
| Therapeutic Class | Androgen |
| Synonyms | Testosterone Caprate; Testosterone 17β-Decanoate |
| Pharmacopoeial Monograph | Ph. Eur. 1736 / BP 2025 |
The identity, molecular formula, molecular weight, CAS number and UNII are supported by PubChem/FDA GSRS.
Testosterone esters act as prodrug forms of testosterone. Following administration, the ester is hydrolyzed to release testosterone, which acts through the androgen receptor. Testosterone-receptor signaling regulates the expression of androgen-responsive genes involved in male reproductive development, maintenance of secondary sexual characteristics and other androgen-dependent physiological processes.
Testosterone esters have historically been developed for testosterone replacement and androgen-related pharmaceutical applications. Testosterone decanoate is also recognized as a testosterone ester used in pharmaceutical and analytical contexts.
Because testosterone decanoate is a pharmacologically active androgen, its manufacture, handling and distribution are subject to applicable regulatory requirements in the destination market.
Testosterone Decanoate has a specific Ph. Eur./BP monograph, which provides considerably stronger support for CMS specifications than a generic commercial specification.
The current BP 2025 presentation of Ph. Eur. monograph 1736 specifies:
The pharmacopoeial assay is performed by liquid chromatography, so it is appropriate to use the numerical content requirement in your CMS's Assay field.
Testosterone decanoate is a synthetic steroid ester manufactured through controlled chemical synthesis and purification. Appropriate manufacturing controls include starting-material qualification, reaction control, purification, crystallization, drying and chromatographic characterization.
A qualified Testosterone Decanoate API Manufacturer in India should maintain validated analytical procedures and demonstrate compliance with the applicable Ph. Eur./BP monograph or customer-specific specification.
Testosterone decanoate is described in the BP/Ph. Eur. monograph as a white or almost white powder. It is practically insoluble in water, very soluble in acetone, methylene chloride and anhydrous ethanol, and freely soluble in fatty oils.
Independent analytical reference data report a melting point around 48–49.5°C, while another reference reports 48–54°C. These are useful physical-characterization values rather than the current pharmacopoeial release specification.
The current BP/Ph. Eur. monograph specifies storage at 2°C to 8°C.
Bulk API packaging should protect the material from moisture, contamination and unsuitable temperature conditions and should follow the validated stability and packaging system.
A professional Testosterone Decanoate API supply package can include:
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 97.0–102.0% |
| Loss on Drying | NMT 0.5% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 0.5% |
| Specific Rotation | +75.0° to +80.0° |
| Melting Point | 48–49.5°C |